With their much flatter profile the new OSRAM Ostar Stage LEDs provide the basis for compact spotlights with an extremely narrow beam and high luminance. These LEDs are ideal for moveable stage lights, known as moving heads, which provide powerful light beams for rock concerts and other impressive lighting arrangements.
Instead of the usual lens, OSRAM Ostar Stage LEDs have a flat glass cover with an anti-reflective coating, giving the LED a much flatter profile. It is now only 1.23 mm high – one quarter of the usual height. Spotlights can therefore be made much more compact.
The glass cover on the new LEDs has been optimized for injecting the light into lens systems. Its etendue (the emission angle/area ratio of the emitting light surface to the projected light surface) in conjunction with customer optics enables a very narrow beam of light (+/- 9°) to be produced. This beam is smaller by factor 2 than for spotlights based on plastic-encapsulated LEDs. This optimum bundling of the light increases the luminance of the spotlight also by factor 2.
Surface emitters thanks to thin-film technology
These powerful light sources are based on the successful OSRAM Ostar SMT platform and contain four different chips in red, green, blue and white. This means they can produce virtually any color. All four chips are manufactured using efficient thin- film technology so that almost all the light produced internally is emitted at the top and more light can be focused in the customer optics system. In pulse mode the individual chips can be operated on a current of up to 2 amps (A), and up to 1 A in continuous mode. This gives maximum values of 146 lumen (lm) in red, 234 lm in green, 1.3 W in blue and 286 lm in white. The overall brightness of an LED at a typical output of 10 W may be up to 700 lm. The dimensions of the LEDs are modest indeed, with a footprint of only 5.9 mm x 4.8 mm. At 3.1 K/W the thermal resistance is very low and heat removal is no problem at all. In constant use the LEDs will last for more than 50,000 hours, giving the moving heads a very long life.
Wide range of applications
The LEDs can be used in spotlights of any size, from small stage spots to large moving heads. Volker Mertens, LED Marketing Manager at OSRAM Opto Semiconductors explains: “OSRAM Ostar Stage has a wide range of applications with different colors and configurations – a real treat for lamp designers. More color combinations are in the pipeline for the Ostar platform. By mixing the different OSRAM Ostar types it is possible to create an enormous range of colors, including pastel shades.”
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